酸化スズ系ガスセンサにおけるアルコールガスの無害化

抄録

Works of conventional tin oxide gas sensors are often disturbed by a contact with ethanol vapor. In order to remove such a disturbance, it was tried to insensitize the sensor to ethanol by use of oxidation catalysts. Of the twelve different catalysts tested, alumina supported Pt catalyst (Pt(1%)/Al₂O₃) was found to be the most effective for total oxidation of ethanol vapor; ethanol was completely oxidized above ca. 200°C under the experimental conditions. The effects of Pt(1%)/Al₂O₃ catalyst in the actual sensing performance were examined by using three types of sensor elements. As a result, the best data were obtained with the coated element which was prepared by coating the conventional sensor element (base element) with Pt(1%)/Al₂O₃ catalyst. The sensitivity of the base element to ethanol vapor was higher than those to CH₄ and C₃H₈ below 400°C and was still significant at 500°C, The coated element, however, was almost insensitive to ethanol vapor in the temperature range 300-500°C, while it was as sensitive to CH₄ and C₃H₈ as the base element. It was also confirmed that the rate of sensor response was little affected by the catalyst coating.